Nanotechnology for more sustainable farming?

The results from the first ever meta-analysis of its kind suggest that nanotechnology could help improve the design of today’s agrochemicals. It might thus help reduce the impact that modern agriculture has on the environment and human health in the future, and also contribute to global food security.

According to the United Nations, the world’s population will reach 9.7 billion in 2050, explains study lead author Melanie Kah of the University of Vienna in Austria and CSIRO in Australia. This means that overall agriculture production will need to increase by 60%, compared to 2005 levels. This increase should of course be sustainable – that is, the quest for high yields and more efficient agricultural practices should not damage the environment or human health.

Nano-based versions of existing pesticides and fertilizers

Nanotechnology shows promise here and researchers have already begun to develop nano-based versions of existing pesticides and fertilizers. These nanoagrochemicals have several advantages over conventional formulas – for example, they might be delivered directly to a pest and/or may be more efficient.

The types of nanopesticide being developed are mainly reformulations of registered active ingredients that have insecticidal, fungicidal or herbicidal properties, explain Kah and colleagues. They can either contain “soft” nanoparticles (such as polymers or solid lipids) or “hard” materials like silica nanoparticles, carbon nanotubes or graphene oxides. Most active ingredients are organic molecules, but some are also inorganic. Copper, for instance, has been used as a fungicide for centuries.

Quantitative evaluation

The problem is that many existing pesticides are not very efficient and their widespread use has already contaminated both terrestrial and aquatic environments. One of the promises of nanoagrochemicals is that farmers might need to use less of these overall.

In their study, published in Nature Nanotechnology doi:10.1038/s41565-018-0131-1, Kah’s team set out to quantitatively evaluate how nanoagrochemicals compare to conventional pesticides and fertilizers. To do this the researchers collected and analysed data from around 80 recently published papers. They found that some reported nanoformulations can alter the properties of pesticides and fertilisers, but not all. Indeed, some changes may not necessarily reduce impact on the environment, they say.

“A critical assessment of nanoagrochemicals is crucial”

“For instance, while some nanoformulations are potentially 10 times more efficient than their conventional counterparts, our analysis shows that the median gain in efficacy is generally only about 20-30%,” says Kah. “On the plus side, reducing the use of agrochemicals by 20-30% could significantly mitigate environmental contamination. At the same time though, one might question whether the typical benefits reported in the literature – that is, observed in the laboratory – will actually translate to the field. For example, when real-world agricultural practices, inherent environmental variability, and issues related to scalability and cost-efficiency are taken into account.”

Such critical assessment of nanoagrochemicals is neverthless crucial for evaluating their associated benefits and risks, however, she tells nanotechweb.org. “There is currently no comprehensive study that evaluates the efficiency and environmental impact of nanoagrochemicals under field conditions. Our analysis also highlights that many published studies lack nano-specific quality assurance and adequate controls. We hope that our work will guide researchers in designing improved studies in the future that better evaluate the benefits and new risks that nanoagrochemicals represent compared to existing products.”

Developing competitive new products

Agriculture needs to modernize and innovate to meet the increasing demands in food of the growing global population, she adds. To this end, we need to carry out more research to develop novel products that are competitive and can help in making tomorrow’s farming more sustainable.

“I will continue to provide guidance and develop tools and techniques underpinned by sound science to support the development of such products,” states Kah. “There is a definite need to empower both regulatory bodies and industry to facilitate innovation in this sector.”

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